Anthropic Adjusts Claude to Prevent AI Misuse in Specific Games

Recently, users have been voicing their frustrations with Claude Opus 5.5, particularly regarding its sudden inability to collaborate with Reverse Engineer Anything, the tool that enabled the decompilation and open-sourcing of video games. At that time, there were no official updates or rule changes from Anthropic.

However, it has now been confirmed that Anthropic is taking a stand against users’ tendencies to engage in vibe-coded IP theft. A new rule, identified in Claude Opus 5.5’s code as “tengu_heron_brook,” directs the AI to prevent prompts that lead to “a recreation of a specific existing game, even if it is renamed or labeled as original.”

This rule was first noticed by a user on X and made its debut in the changelog for Claude Opus 5.5 on October 27. While it restricts recreations of specific existing games, it still permits users to “build original games, games in a genre, and games from the user’s own designs and assets.”

ANTHROPIC IS CRACKING DOWN ON VIDEO GAME REWRITES ????

Claude Code picked up a new rule around Oct 27, sent from Anthropic’s servers under a flag called “tengu_heron_brook”. There’s no setting to turn it off.

The full rule: “Do build original games, games in a genre, and games…pic.twitter.com/0Zc5mQWHJt

— chasm (@chasmmmmmmmmmmm)October 30, 2026

In essence, this marks a significant shift beyond merely targeting decompilations; Claude will now actively prevent users from creating original games that draw inspiration from existing titles.

For example, requesting a racing game should be acceptable, but asking for a racing game “like Need For Speed” would activate Claude’s safeguards. Reports from users on r/Anthropic suggest that Claude is now resisting all forms of IP reproduction, whether game-related or not.

“Lol yesterday I wanted to learn some info/spoilers from the web novel I was reading,” a user shared in a post on r/Anthropic. “Claude refused to read unlicensed translation for me, saying that’s illegal and immoral. The theft machine itself refuses to read scanlations.”

While it’s amusing to see a Claude user refer to it as “the theft machine,” there are numerous posts on r/Claude expressing dissatisfaction with the newly implemented “safety classifiers” that seem to restrict access to everything from security research to published coding books. It appears that Anthropic may have faced some backlash for its users’ actions and has decided to—if you’ll pardon the pun—reverse course.